1. Field of the Invention
The present invention relates to a bicycle hub, and more particularly to a method for making positioning structures of a bicycle hub.
2. Description of the Prior Art
Bicycle is a traffic tool for leisure sport and racing, which is not only environmental friendly, but also can provide exercise for the rider. The bicycle hub is an important component for connecting the bicycle frame and the wheel. As shown in FIG. 1, the bicycle hub 10 comprises a hollow cylindrical hub shell 11. Each end of the hub shell 11 is formed with a ring-shaped fixing piece 12 in the radial direction, and one side of each of the fixing piece is formed with a circular flange 13. Under the original thickness, the inner wall of the flange 13 is cut thin to form a positioning structure 14. A bearing A is embedded in each of the two flanges 13 and is positioned by the positioning structure 14. However, this conventional bicycle hub still has the following problems:
1. After the flange 13 of the bicycle hub 10 is cut thin, it will damage the structure strength of the original flange 13, but this bicycle hub 10 will not only be subjected to a heavy load but to a high speed rotation, therefore, the flange 13 will definitely be deformed after a long-term of use. Moreover, if the bicycle hub 10 breaks during a high speed ride, it will severely affect the riding safety. The bicycle can be bought after destroyed, but the life safety can not be neglected;
2. The positioning structure 14 is formed by cutting the flange 13 of the bicycle hub 10, in order to accurately control the thickness during the cutting process, the machining speed must be affected and the machining time must be prolonged, thus causing the waste of the cost.
The present invention has arisen to mitigate and/or obviate the afore-described disadvantages.